System for producing modulated waves



R. A.-HEISING.

SYSTEM-FOR PRODUCING MODULATED WAVES.

APPLICATION FILED 050.27, 1918.

1 4362520 mama Nov. 21, 1922 ?atented Nov, 2i, i922,

warren stares intern PATENT carton RAYMOND A. HEIQING, OF EAST ORANGE,JIEBSEY, ASSIGNOB TO WESTERN ELEC- TRIO COMPANY, INCORPORATED, OF NEWYORK, H. Y., A CORPORATION OF NEW YORK.

SYSTEM FOR PRODUCTNG MODULA'IYE WAVE To all it may concern Be it knownthat l, RAYMOND A. HEISING,

a citizen of the United States, residing at is produced by uniformlyrecurring disvention, reference is made, to the accompanying drawingswherein Fig. 1'" represents. a system having a discharge device inseries charges of amounts of electricity which vary in accordance withsignals (2) To provide such means which are adapted for the transmissionof speech: (3) To provide systems in which large currents, modulated inaccordance with signals, may be efliciently generated by an arc: (4:) Toprovide systems in which the frequency of arc discharges is maintainedconstant independently of variations in their amplitude: (5) To provideellicient variable impedance means for as- Consideration of thefollowing descrip' tion will an gest other objects and advanta hevariation in voltage of the vcurrent supplied to the arc is caused by avariable impedance either in shunt to, in series with the are orotherwise suitably related thereto. The variable impedance preferablyconsists of a deviceof the electrondischarge type. For telephony thedischarge device is controlled by a microphone or equivalent element.Use is made of a third of auxiliary electrode ofthe are for controllingthe main arc dischar e. B adjustingt'he constants in the auxifiary eectrode'circuit, the frequency can tie-controlled indeendw ently, in alarge degree, of the amptude variation due to the signals. a For moredefinite explanation; of the in- -tudes of'inductance 13 and capacity sof the invention.

with an arc; Fig. 2 a system having a discharge device in parallel withan arc; Figs. 3 and 4 are other modified forms, while F 1g. 5 .disclosesan arrangement which may be utilized in connection with any of the preceding arrangements.

Re erring-particularly to Fi l, a generator 5 constitutes a source 0)direct current for supplying an arc circuit which comprises theanode-cathode path of the electron discharge device 6, the highfrequency choke coil 7 the electrode 8, electrode 9 and conductors 10and 11. The device 6 typifies either a single vacuum tube or a suit ablesystem of such tubes in parallel or series relation. The material ofwhich the electrodes 8 and 9 are composed, the space therebetween, andthemaximum voltage across the electrodes, are so chosen that normallythe discharge will not occur except as it is controlled, triggered,primed or tripped oil by the discharge across the electrodes 12 and 9.The frequency of the discharges across elec trodes 9 and 12is controlledby the magni- 14 in the control circuit 15, which circuit includeselectrodes 12 and 9. The control circuit is energized by the source 5but it is optional to provide a'separate control source. Theelectromagnet l7 malntams a field across the space between. electrodes8, 12 and 9 which" serves to extinguish the are after each dis- 19 and agrid. or impedance controlling clement 20. Gonnected to the grid and thecathode is the input circuit 21 comprising resistance 22, shunted by thesecondary 23 of a transformer to which is coupled the inary 24, saidprimary 2% being located in series with the controlling microphone orequivalent device 26 in the circuit 25. The usual sources 27 and 28 arerovided for heating the cathode and mai taining the grid netive' withrespect thereto respectively. The are across'the electrodes 8 and 9 isincluded in the path to ground or the antenna circuit which com risesinductance 29' 'andthe serial 30. Wit "proper adjustmentsthe radiatedfre uency will be an approximatesine waveo the same frequency icemicrophone 26, will cause negligible change of current through coil 31,due to its high inductance. The generator 0 may be regarded as a sourceof current which is maintained constant by coil 31, or the generator 5and coil 31 together may be regarded as a source of constant current.

In Fig. 3 the out-put circuit of device 6 comprises primary 32 and asuitable source of direct current, such as a generator 33 or a battery.(oil 32 is coupled to coil 34 which thereby serves to impress lowfrequency variations of voltage across the path comprising the arcelectrodes 8 and 9 which correspond to variations across theanodecathode circuit of device 6. Coil 7 serves to prevent the shuntingof high frequency oscillations around the arc to ground. Thisarrangement difiers from that of Fig. 1 in that the device 6, instead ofbeing in series with the current supply path of the arc is coupled tothis path by means of a transformer 32, 34.

In Fig. 4 the-device 6, instead of being in a path parallel to the arcsupply circuit,

as in Fig. 2, is coupled by means oftransformer 35, 36'to a shunt path37 which comprises capacity 38 and secondary 36. The microphone actsupon device 6 to vary the space current therethrough, and thesevariations in turn cause corresponding voltages to be induced in path37. The electromagnet 17 may be supplied by aseparate source 38. Thecontrol circuit may also be energized by separate source 5 in serieswith which aninductance 40 may be placed, if necessary.

The function of those-elements of Figs. 2, 3 and 4 which are not givenin detail, may be readily understoodby reference to the description ofthe correspondingly numbered elements of Fig.4?

Fig. 5 illustrates a modified arrangement which may be utilized inconnection with any of the preceding. The main oscilla tioncircuit 29,30 is here substituted for the antenna circuit of the preceding figures.The antenna circuit 39 is coupled to the oscillation circuit by coil 29.By means of this arrangement the oscillations existing in the antennawill have a smaller proportion of harmonic frequencies. Intermediatetuned circuits may be placed between the oscillation circuit and theantenna 39 to more eifectively eliminate the harmonics. Such tunedcircuits are well known and therefore need no description... Bysubstituting a transmission line for the antenna,

this invention may be utilized-for transmitting intelligence overconductive. circuits.

Operation: The generator 5 supplies a direct voltage to the circuit 15andcondenser 14. which periodically discharges across the electrodes 9and 12 and causes amount of energy, it may serve to control thedischarge of a much larger amount of energy across the electrodes 8, 9.The device 6 acts as an amplifier and reproduces in amplified form theimpedance changes in or the current changes through the device 26. Theantenna capacity or the equivalent capacity 30' is continually beingcharged by the source 5, butthe rate of charge varies in accordance withthe condition of device 6.'

Novel features inherent in; the invention are defined in the appendedclaims.

lVhat is claimed is: 1. system comprising an arc generator, a directcurrent supply source for saidgenerator, means for varying in accordancewith sound waves the potential supplied by said source at' a rate lowerthan the frequency generated by said generator, and

means to prevent the operation of said first- I mentioned means frommaterially changing the frequency generated by said generator. 2. Asystem comprising an arc generator, adirect current supply sourcetherefor, and a non-periodic path including a signal controlleddischargedevice in shunt to said generator for Varying at a lowfrequency rate the potential supplied by said source. 3. A systemcomprising an arc generator, a direct current energy source therefor,and an untuned path including a discharge device for shunting from saidgenerator in accordance with sound Waves the energy supplied by saidsource.

' 4. A system comprising an arc generator,

-a direct current supply' source therefor, a

iii

nreaeea source of constant current for supplying said devices.

6. A system comprising a source of electric current, an are fortransforming the energy from said source into high frequency alternatingcurrent Whose amplitude is dependent upon the instantaneous magnitude ofthe voltage supplied by said source, a discharge device for controllingthe voltage supplied by saidsource, and means for supplying said devicewith current from said source.

7. A system comprising an are for transforming electrical energy intohigh frequency alternating current energy, an energy supply for said arevarying at a signaling frequency, and means operable without substantialtime lag for preventing variations in said energy supply from ailectingthe frequency generated by said arc.

8. A. system comprising anarc for transforming electrical current energyinto high frequency oscillations, a current supply source for said arc,a speech controlled electric device for varying the current supply oisaid are, and means operable with a time lag measurably less than theperiod of an audible sound wave for preventing variations in the currentsupply from varying til? the period of said oscillations.

9. A system comprising an arc generator, a signal conductor in whichsaid generator produces high frequency waves, a current supply line forsaid generator, a unidirectionally conducting electron discharge deviceoperatively connected to and energized by current transferred throughsaid line, and signal controlled means for varying the impedance of saiddischarge device.

lil. A system for generating modulated high frequency waves, comprisingan arc generator, a current supply source therefor, means adapted to bevaried at a rate within the range of audibility for varying the currentsupplied from said source, and means for preventing variations at saidrate in said current supply from varying the frequency of saidgenerator.

11. A system comprising a main oscillation-circuit, an arc device forgenerating oscillations in saidcircuit, a current supply means for saidare device, means adapted to be controlled in accordance with soundsignals for varying the-current supplied from said source, a controlcircuit for said are, and means associating said circuit with said arewhereby the tendency of signaling variations in current supply to saidare to change the frequency of oscillations is counteracted.

12. A system comprising a main oscillation circuit, anarc device forgenerating oscillations in said circuit, a current sup ly means for saidarcdevice, an-electron ischar e device for varying the current supphefrom said means, and a tr1gger control circuit including inductance andcapacity for said are.

13. A system comprising asource of direct current, an arc, and anelectron discharge device, said are and said discharge device being inpaths conductive to direct current which are in parallel with respect tosaid source.

14. A system comprising a source of enerizing current, an arc, anelectron discharge device and means for varying the impedance or saiddischarge device, said are and said discharge device being in pathsconductive to direct current which are in parallel with respect to saidsource.

15. A system comprising a source of direct current, an arc, an-electrondischarge device, said are and said discharge device being in pathsconductive to direct current which are in parallelwith respect to saidsource, and means to maintain the current through said sourcesubstantially constant.

16. in combination, a source of substantially constant current, an arc,and an electron discharge device, said are and said device being inpaths conductive to direct current which are in parallel with respect tosaid source. a 1?. A system comprising an are, an electron dischargedevice, the terminals of said are and said device being connected byconductors or" negligible impedance for direct and speech frequencycurrent, and a common source of electrical energy for supplying currentto said are and said device.

18. A system comprising an are, a unidirectionally conducting electrondischarge device having a space current path, and a common source oicurrent supply for said are and said path.

19.. A system comprising a source of direct current, a speech irequencychoke coil, ahigh "frequency choke coil, and main arc electrodes, saidaforementioned elements being located in a series irouit, a conductivepath shunted across the high frequency choke coil and the are, anelectron dischar e device operatively associated with said path, meansincluding a microphone and an input circuit for controlling theimpedance of said device, a high frequency oscillation circuit shuntedaround said electrodes, acontrol circuit includin inductance andcapacity shunted around said source of di= rect current, an auxiliaryelectrode for said are, one portion of said control circuit beingconnected to one of said main electrodes and another portion to saidauxiliary electrode, and means for maintaining a mag netic field acrossthe space between said main and-auxiliaryelectrodes.

20. i l-system comprising an arc, a source of current therefor, anelectron discharge device having an anode, an electron emltting cathode,and an impedance controlling element, said are and said device being innon-periodic paths which are in parallel with respect to said source.

21. A system comprising a source of cur-. rent, means to vary thevoltage supplied by said source at a low frequency rate, a dis chargepath for said source, and means operating independently of dischargesacross said path to cause discharges across said path at a highfrequency rate which is substantially independent of the instantaneousvoltage supplied by said source.

22. In combination, an arc, means for impressing thereon "an electricpotential varying in accordance withsignals, means for extinguishingsaid are, and means for priming said are at a constant frequency rate.

23. The method of producing modulated oscillations in a circuit whichcomprises charging a capacity in the circuit, varying at a low frequencyrate the charging current for said capaclty, and causing the dischar eof the capacity at a constant and relative y high rate. v

24. The method which comprises causing a current to continuously flowtocharge a capacity, varying the amperage of said current in accordancewith speech, and periodically priming a discharge path to cause thecapacity to discharge therethrough at a frequency which is high ascompared with speech frequencies.

25. The method which comprises forcing a continuous current into acapacity, varying the rate of flow of the current at a comparatively lowfrequency, and priming a dlscharge path to cause the capacity 'to'discharge therethroughat a radio frequency rate.

26. The method which comprises forcing a continuous current into .acapacity vari ably impeding a shunt path around said capacity at acomparatively low frequency and dischar 'ng the capacity at a constantand relatively high frequency rate.

27. A system comprising an arc, a source of current therefor, highlyevacuated unidirectionally conducting electron discharge device, ananode-cathode discharge pathwithin said devlce, and means for varyingthe comprising an arc and a space discharge device having ananode-cathode path, with means for controlling the impedance of saidpath, which comprises maintaining constant the sum of the currentsthrough said are and said device.

.29. A system comprising an arc device, a space discharge device havingan anode and an electron emitting cathode comprising terminals of adischarge path, a common source of electrical energy for said path andsaidv arc, and means for varying the current to said are by, variablydissipating energy in said device.

30. A system comprising an arc, a s ace discharge device having an anodean an electron emittin cathode comprising terminals of a disc arge path,means for energizing said cathode, a common source of current for saidare and device, and means for preventing variations in current supplyfrom said source.

31. An are system having main electrodes and means forimpressing avariable voltage thereaoross, an auxiliary electrode, a priming circuitconnected to said auxiliary electrode, and a steady current supply forsaid priming circuit, said priming circuit and auxiliary electrode beingarranged to prime said are at regular intervals irrespective of voltagevariations across said main electrodes.

In witness whereof, I hereunto subscribe my name this 20th day ofDecember A. D.,;

RAYMOND A. HEISING. I

